Imaging instruments, such as ultrasound probes, computed tomography scanners (CT Scanners), and magnetic resonance imagers (MRI) have revolutionized the manner in which many important medical procedures are performed. Each of these medical instruments utilizes non-invasive imaging techniques to explore and assess the condition of sub-dermal tissue. As a result of this non-invasive imaging ability, diagnostic and therapeutic protocol's have been developed that allow for the provision of many highly successful and safe procedures with a minimum of disturbance to patients.
Ultrasound, for example, has received widespread acceptance as a useful diagnostic tool. Ultrasound is particularly well suited for obstetrics, where real-time scanners create a continuous image of a moving fetus that can be displayed on a monitoring screen. The image is created by emission of very high frequency sound waves from a transducer placed in contact with the mother's skin. Repeated arrays of ultrasonic beams scan the fetus and are reflected back to the transducer, where the beams are received and the data transmitted to a processing device. The processing device can analyze the information and compose a picture for display on the monitoring screen. Relative measurements may be made, and the gestational age, size and growth of the fetus can be determined. In some circumstances, a needle is guided into the amniotic fluid in order to retrieve a fluid sample for analysis. These samples can be useful for diagnosing irregular conditions and indicate that prenatal care is necessary for the fetus.
Ultrasound probes, and other imaging instruments, are also used for a variety of other purposes, such as identifying the existence, location, and size of tumors, as well as the existence of other medical conditions, including the atrophy or hypertrophy of bodily organs. While many imaging techniques are primarily performed on humans, similar techniques are often used by veterinarians to diagnose and treat a wide variety of animals, such as sheep, cows, horses, and pigs.
For many imaging applications, it is desirable that a needle, biopsy instrument, catheter, or other thin instrument be inserted into the body of a patient in order to remove a biopsy sample or to perform other medical procedures. It is normally desirable that the thin instrument or needle be guided to a specific position within the body of the patient. Various guide devices have been designed for assisting in guiding the instrument. Many of these guides are fixed-angle devices with limited functionality because they have limited control over needle placement compared to a needle guide that allows selection of multiple angles. In addition, many of these devices do not permit the placement of more than one needle into a patient or they do not make such multiple placements easy.
Another specific problem with many current needle guide systems is that they are not well suited to be used with a sterile cover, such as a latex film, placed over the imaging instrument. Such covers are increasingly desirable in order to maintain the ultrasound sensor in a sterile environment. The covers reduce the likelihood of contamination between patients and reduce the cost of medical procedures by minimizing sterilization costs. One challenge of working with latex and similar polymer based covers is that they have a high coefficient of friction and are subject to binding when in contact with moving pieces of an imaging sensor or needle guide. Such binding can lead to tears or punctures of the cover. For example, some prior art imaging sensors have removable pieces that are frictionally fit over a latex cover. Such designs are problematic because they can be difficult to fit and remove, as well as cause problems with binding and an ensuing risk of tearing.
Consequently, a need exists for an improved needle guide system. Such improved needle guide system should permit a needle to be directed into a patient at a variety of angles and allow for the easy removal of the needle from the system without damage to a protective cover.